Electromagnet



Nov. 28, 1933. R H, BAHNEY 1,937,216

ELECTHOMAGNET Filed July l5, 1953 Patented Nov. 28, 1933 UNITED STATES PATENT OFFICE v' 17 Claims.

This 'invention relates to the art of magnetically handling metal articles, and more particularly relates to anew method of and apparatus for handling nonmagnetic articles.

The term metal articles as used herein includes all articles through which an electric current may be passed and about which a magnetic flux is set up capable of being acted upon by an electromagnet to handle or lift the same. This term also includes articles which may be magnetic at ordinary temperatures but which are non-magnetic at other temperatures such as relatively high temperatures.

Heretof'ore, electrically energized magnets have been used widely for handling magnetic metal articles, but so far as I am aware no method or means has ever been devised heretofore to handle non-magnetic metal articles magnetically. l I

The present invention is predicated on my discovery that non-magnetic metal articles may be handled magnetically if suitably energized while being subjected to magnetic handling forces. I have found that a non-magnetic metal article may be suitably energized by passing electric current thru the article. Another way of describing the invention is to say that nonmagnetic metal articles may be handled magnetically byI creating a ux about the article while the article is in the field of flux of the magnet or other magnetic handling means.

In the drawing accompanying and forming a part of this specification various embodiments of the present invention are disclosed. In this drawing:

Figure l is a more or less diagrammatic elevational representation of an ordinary horse-shoe type lifting magnet adapted to handle non-magnetic articles according to the present invention.

Figure 2 is a more or less diagrammatic bottom plan view of the apparatus shown in Figure 1.

Figure 3 is a more or less diagrammatic eleva-v tional representation of a modi'ed form of lifting magnet adapted to handle non-magnetic metal articles according to the present invention, and

Figure 4 is a more or less diagrammatic plan view of the apparatus shown in Figure 3.

Figure 5 is a diagrammatic showing of a roller conveyor embodying my invention.

Figure 6 is a detail view taken axially thru one of the magnetic rollers of Fig. 5.

Figure 7 is a diagrammatic showing of an alternating current lifting device embodying my r invention.

rect current.

In Figures 1 and 2, 1 designates the core of a conventional horse-shoe type direct current lifting magnet, and 2 designates a suitable winding for the core adapted to be connected to a suitable source of relatively high voltage current (not shown). Between the north and south poles 3 and 4 respectively of the core, and insulated therefrom, are disposed a plurality of, for example, two contact members 5 and 6, constituting terminals of a circuit connected to a suitable source (not shown) of relatively low voltage di-` The contact members 5 and 6 are spaced apart from each other and are adapted to contact with the non-magnetic metal article 7 to be handled when it is in the field of iiux between the poles of the magnet. When members 5 and 6 are brought into contact with a non-magnetic article 7 and suitable low voltage current is passed thru the latter, as indicated, the article is suitably energized and is attracted by the magnet when suitable current flows in the winding 2.

If the direction of oW of current in either article 7 or coil 2 is reversed, the article will be repelled by the magnet.

I believe that this phenomenon may be explained as follows: A ux is set up around article 7 when current flows thru it. When article 7 is in the eld of flux between poles 3 and 4, these fields intersect.` If these elds of flux are in the directions shown in Figs. 1 and 2, they cooperate in causing attraction of the article to the magnet, but if the direction of either field is reversed the fluxes oppose each other and the magnet will repel the article. k

The term handled or handling is used in this application in the broad sense and is intended to mean and include lifting, carrying, conveying, and any and all other operations of moving nonmagnetic metal articles by magnetic means.

Figures 3 and 4 of the drawing illustrates a modied form of a lifting magnet embodying my invention. It comprises a core 8 having disposed thereabout a suitable coil or winding 9 which is electrically connected to a suitable source of high voltage direct current (not shown), The core is formed with a single north pole 10, and two south poles 11 and 12, respectively, disposed on either side of the north pole 10 and in parallel relation thereto. Asshown in Figure 4, the north pole is of somewhat less length than the adjacent south poles and provides space for a contact member 13 to extend over most of the distance between the two south poles. It is insulated and spaced from poles 10, 11, and 12. y On the opposite side of the core 8 and extending between vthe poles are a plurality of contact members 14 and 15. These contact members 14 and 15 extend for most of the distance between the north and south poles but are insulated therefrom and are connected respectively as terminals in a circuit including a suitable source (not shown) of low voltage direct current.

When the Contact plates 13, 14 and l5 are brought into contact, as shown, with two nonmagnetic articles 16 to be handled, a'nd a suitable current of electricity flows through the articles and the members 13, 14 and 15 as indicated, and when simultaneously therewith the core 8 is energized by suitable current flowing in coil 9 in the directions indicated, the articles 16 will be attracted to the magnet and may be handled as desired.

-In order that those skilled in the art may be able to practice my invention without experimentation, I give the following figures of currents, and article sizes and weights, which I have successfully employed in carrying out my invention.

A horseshoe magnet like that shown in Figs. 1 and 2, had a core composed of soft iron, was about 3 inches wide and had a space of about 1% inches between poles. About 2,000 turns of No.' 26 copper wire encircled the core between the poles. A current of about 10 amperes at about 200 volts was passed thru the winding 2 and completely saturated the core. A current of about 60 amperes at about 1 volt was passed thru a piece of copper strip at about 70 F. and measuring about 1/64" x 3A" x 5". The magnet lifted and carried this strip satisfactorily. With the same magnet and current in coil 2, a piece of aluminum strip of the same size required a current flowing therein of about 40 amperes at about 1.2 voles, while a similar sized piece of stainless steell required a current of about 60 amperes at about 1.5 volts.

The copper and stainless steel articles were of about the same weight but the resistance of the steel was higher. The aluminum was lighter than either the copper or steel. Apparently the weight of non-magnetic metal which may be handled by this invention is a function of the amperage used and indicates that the Weightlifted is a function of the strength of the ilux about the article or the current passing thru the article.

These illustrations furnish a basis for ready calculation of magnet sizes and currents required for handling different non-magnetic metals in articles of different sizes.

I have found that it requires relatively low voltage to force a current of sufiiciently high amperage through the article to se* up a flux about the article which may be acted upon by an electromagnet and, further, that such passage of current does not cause burning of the article or the electrodes. Burning or heating of the article results from high wattage, which is not a characteristic of the current-and voltage I employ.

My invention may also be applied to roller conveyors. In Figs. 5 and 6 apparatus illustrative of such use is shown more or less diagrammatically. 17 designates magnetic rollers, of which any desired number may be employed, and 18 indicates other conducting rollers preferably arranged alternately with rollers 17. Rollers 18 correspond to conductors 5 and 6 of Figs. 1 and 2 and are preferably included as shown in Fig. 5 in a low voltage circuit. Rollers 17 may consist of the core 19 having enlarged disc-shaped ends 20, a coil 21 about the core between the discs and connected thru slip rings, brushes or the like, (not shown) in a magnetizing circuit, and a tubular cover 22 of non-magnetic steel or other suitable material. When a. non-magnetic article 23 contacts with two adjacent rollers 18 of opposite polarity, current will flow thru the article thereby energizing it so that the adjacent magnetic rollers 17 energized by the current flowing in coils 2l will attract and handle the non-magnetic article. Rotation of some, or all, the rollers will propel the article.

The apparatus shown in Fig. 5 shows an overhead conveyor, but it will be obvious that the articles may be conveyed on top of the rollers with even greater facility. Idler rollers may be placed between the rollers shown in Fig. 5. if desired.

My invention may also be practiced with alternating current. Fig. 7 shows a diagrammatic adaptation of the apparatus of Figs. 1 and 2 to such current. In Fig. 7, 24 designates a laminated field core having a coil 25 thereabout, and pole pieces 26 and 27. Within field core 24 is disposed a laminated core 28 of a low voltage transformer, the primary of which is the coil 29 and the secondary of which is a U-shaped conductor 30 having laterally extending electrodes 31 disposed between but insulated from the poles 26 and 27 of field core 24 and adapted to contact with an article 32 to be handled. The alternations of the currents flowing in coils '25 and 29 should be so synchronized and in phase that the article will always be attracted by the device.l

The current strengths should be such as to energize and lift the article to be handled and the frequency of the currents should not be so high as to prevent substantial penetration of the flux into the article and thus partly or largely nullify the intended energizing effect of the currents.

Many other adaptations and embodiments of myl invention will readily occur to others skilled in the art, but the foregoing disclosure is believed to be sufllcient to enable those skilled in the art to understand and practice my invention. The scope of my invention is defined in what is claimed.

What is claimed is:

l. Apparatus for magnetically handling nonmagnetic metal articles including an electromagnet core having spaced apart poles and a high voltage winding about the core, low voltage terminal members disposed in spaced relation to each other within the field of flux between the magnet poles and adapted to contact with a nonmagnetic metal article to be handled, and means for passing low voltage current through the said terminals and the nonmagnetic metal article contacting therewith.

2. Apparatus for magnetically handling nonmagnetic metal articles including an electromagnet and spaced members forming terminals of a low voltage circuit and positioned to contact with a non-magnetic article in the fleld of ux of the magnet.

3. Apparatus for magnetically handling 'nonmagnetic metal articles including an electromagnet having poles, electrical terminals spaced apart from each other and from said poles and engageable with a non-magnetic metallic article in the field of flux between the magnet poles.'

4. Apparatus for lifting non-magnetic metal articles including an electro-magnet having poles. spaced conducting members disposed between but disconnected from the poles, and means for passing low voltage current through a non-magnetic metal article contacting said members and disposed in the iield-of ux between the poles of the magnet.

5. Apparatus for handling non-magnetic metal articles including an electro-magnet having poles, conducting members spaced apart from each other and disposed between the poles of said magnet, and means to pass low voltage current thru said members and a non-magnetic metal article in contact therewith.

6. A conveyor for handling non-magnetic metal articles including spaced conducting rollers constituting terminals of a low voltage circuit, and a magnet roller disposed between the conducting rollers and having magnetic poles, 'all the said rollers being position to contact with a non-magnetic article to be conveyed.

7. A conveyor for handling non-magnetic metal articles including a plurality of spaced rollers positioned to contact a non-magnetic article to be conveyed, certain of said rollers constituting terminals of a low voltage circuit, and certain of the remaining rollers located between the said terminal rollers, being magnetic rollers having magnetic poles. y

8. Apparatus for magnetically handling nonmagnetic metal articles, including a magnet having a plurality of poles of the same polarity, a

i plurality of conductors between poles of the magnet and spaced apart from each other and from the poles, the conductors being disposed to engage non-magnetic metal articles in the iield of iiux between said poles, certain of said conductors constituting terminals of a low voltage circuit which, when closed, includes the articles to be handled.

9. Apparatus for handling non-magnetic metal articles, including a direct current electro-magnet, and means including terminal members for passing ,low voltage direct current thru a nonmagnetic metal article to be handled while the latter is in the field of flux of the magnet.

10. Apparatus for handling non-magnetic metal articles including an alternating current electromagnet, and contact members constituting terminals of a low voltage alternating current circuit and positioned to contact with a nonmagnetic article in the field of linx of the magnet.

11. The method or handling metal articles including the steps of bringing a non-magnetic metal article within the iield of ilux of an electromagnet and simultaneously passing a low voltage energizing current thru the article.

12. The method of handling metal articles including the steps of bringing a non-magnetic metal article Within the iield of flux of an electromagnet and simultaneously passing a low voltage energizing current through the articlerto set up a magnetic flux about the article in a direction to cooperate with the attracting force of the magnetic iield of the electro-magnet.

13. The method of handling metal articles which includes thesteps of bringing a non-magnetic article within the eld of flux of an alternating current electro-magnet and simultaneously passing low voltage energizing alternating current thru said article, and synchronizing the reversals of the currents in the ymagnet and in the article.

y14. Apparatus for handling non-magnetic metal articles, including an electro-magnet, and means including terminal members for passing a current of low voltage through a non-magnetic metal article to be handled while the latter is in the eld of flux of the magnet.

15. The method of handling metal articles which includes the steps of passing a low voltageenergizing current through a non-magnetic article while positioned within the field of ilux of an electro-magnet and controlled by the latter, and mechanically moving said article while under the control of said electro-magnet.

16. The method of handling metal articles which includes the steps of passing a low voltage energizing current through a non-magnetic article while positioned on a conveyor having article moving means, within the field of flux of an electromagnet and controlled by the latter, and actuating said article moving means to move the article.

17. The method of handling metal articles which includes the steps of passing 'a low voltage energizing current through a non-magnetic article while positioned Withinthe iieldof flux of an electromagnet and controlled by the latter, and moving the article by .moving the magnet while the energized article is controlled by the latter. l

- ROBERT H. BAHNEY. 

